Amylase (enzyme number: EC3.2.1.1) is secreted from pancreas, salivary gland and so on, and is mostly distributed in salivary gland and pancreas. Besides those, it is known to be present in muscle, ovary and oviduct as well. It is further known that amylase which is exuded from tissues is present in blood and urine. It is known that amylase value in serum, urine or pancreatic juice shows a high value in a part of functional disorders of pancreas or salivary gland and kidney or liver, or neoplastic disease. With regard to a method for measuring such amylase activity, an enzymatic method using a modified oligosaccharide substrate, etc. have been known, and the measurement has been carried out as the changes in absorbance using a spectrophotometer or an autoanalyzer. In the studies in recent years, it has been reported that saliva amylase activity value is correlated to stress of a subject [Japanese journal of medical electronics and biological engineering, 39 (3), p. 234–239 (2001), Masaki Yamaguchi, et al.], and a method for measuring amylase activity value in saliva samples has been demanded. However, in the measurement using a conventional autoanalyzer, there are problems such as apparatus for the measurement is expensive, various preparations are necessary before conducting the measurement and several tens minutes are required for the measurement itself.